In the Stackelberg duopoly experiments in Huck et al. (2001), the followers behave less timidly than predicted by conventional theory and the leaders act less aggressively than predicted. We provide a parsimonious explanation to these anomalies by simplifying the model of Fehr and Schmidt (1999) in two directions — there is no advantageous inequality aversion and all players with non-standard preferences have the same degree of disadvantageous inequality aversion. Maximum likelihood procedures show that the predictions of this model are consistent with the data in Huck et al. (2001), and that more than a third of the players have high degree of disadvantageous inequality aversion which is statistically different from zero.